The invention refers to a single-component composition which is liquid at room temperature and can be cross-linked by actinic radiation and by moisture. The composition in accordance with the invention can be used as an adhesive, coating material or filling material. The composition is preferably used for filling electro-optical components.
Compositions that can be cross-linked using actinic radiation are well known. Such compositions usually contain at least one photoinitiator for radical polymerization, as well as radically cross-linkable monomers and/or pre-polymers and, optionally, other auxiliary substances. The photoinitiator is broken down by the radiation, for example by visible or UV light, into reactive radicals with which the polymerization or cross-linking of the monomers is initiated. As the radical polymerization takes place at a very high reaction speed, both storage-stable as well as very rapidly curing compositions can be provided. A disadvantage of the radiation-curing compositions is, however, that the material does not cure in shadow zones.
DE 10 2008 002163 A1 describes hot-melt adhesives containing alpha-alkoxysilanes which can be cured by the exposure to moisture. A disadvantage here is that the curing speed of these compositions is not sufficient to support rapid, automated production processes. The moisture curing is still not complete after more than one week. Curing times within a range of a few seconds cannot be achieved with these compositions.
DE 10 2007 042948 A1 refers to polymers produced by the grafting of heteroatom-substituted silanes in the alpha position, and their cross-linking by water. These polymers are also only fully cured after several hours, and are therefore not suitable for processes which require rapid initial curing.
DE 10351804 A1 refers to a process to increase the elasticity of moisture-cured elastomers made of alkoxy-crosslinking single-component compositions. These compositions only start to form a skin after many minutes in contact with moisture, and are therefore also not suitable for rapid curing processes.
DE 10 2005 029282 A1 discloses silane-crosslinking adhesive or sealing compositions which, alongside a silane-crosslinking polymer, also contain special alpha-silanes with at least two ethoxy groups. A skin only forms on these products after several minutes, so that these compositions cannot be used for rapid, fully automated processes.
DE 10 2007 060536 A1 refers to coating agents for wood and synthetic surfaces. The coating agents contain a polyolefin which has at least two alkoxysilane groups, compounds with (meth)acrylic groups with up to ten radiation-reactive groups, as well as catalysts and photoinitiators. The coating agents are solid at room temperature and can be cross-linked by actinic radiation and moisture. A disadvantage is that the compositions, which are solid at room temperature, cannot be easily applied over the surface of a substrate by simple dosing methods, and the end-capped polyolefins have a low tolerance at room temperature to components of the formulation used for radiation hardening.
EP 0934956 A1 describes curable formulations which contain a saturated hydrocarbon polymer which contains at least one group cross-linking to form siloxane, a silane-curing reagent and a component which can be polymerized in the presence of atmospheric oxygen or with the aid of a photoinitiator. A disadvantage is the very slow curing under moist conditions. Radiation curing is only used to achieve a more rapid initial hardness of the otherwise purely moisture-curing composition.
US 2009/0299017 A1 describes single-component, moisture-curing compositions which have improved adhesive properties and can be easily coated after the composition has cured. The compositions described are not suitable for rapid, automated processes due to their slow curing.
EP 2051227 A1 describes displays which have a cured resin between the display part and the protective layer.
EP 2133855 A1 and EP 2133856 A1 disclose displays with a protective layer which is fixed with the aid of a radiation-curable composition.
EP 2136348 A1 discloses a display which has a cured material between the display part and the protective layer.
US 2009/0186552 A1 describes radiation- and heat-curable resins to connect a protective layer with a display part in a display.
US 2009/0296033 A1 discloses displays which contain a curable resin between the protective layer and the display part.
It is, therefore, still an object to provide storage-stable compositions which can be processed in liquid form and then cured very rapidly while ensuring that they are fully cured throughout the whole volume of the composition. In particular, the compositions need to meet the requirements for automated production processes, in particular in the production of electro-optical components.
This object is solved in accordance with the invention by a single-component dual curing composition according to Claim 1.
Advantageous embodiments of the compositions according to the invention are indicated in the sub-claims.
A further object of the invention is the use of the compositions according to the invention as an adhesive or sealant for bonding, filling, sealing and coating of substrates, in particular its use to fill electro-optical components such as displays.